We Have Finally Discovered Why Boners Don’t Have Actual Bones in Them

Photo: David Ryle/Getty Images

Scientists at University College London may finally have an answer to one anatomy question that may have perplexed you over the years: Why don’t boners have bones?

While other mammals have a penis bone — or baculum — humans are notably lacking. Kit Opie, who headed up the study, connects this to human mating habits over time. Male species who have longer penis bones engage in “prolonged intromission” — they have intercourse for a longer period of time so as to keep other competing males away from their mate, and increase their chances of impregnating her.

1.9 million years ago, Homo erectus became monogamous; scientists theorize this is when the human baculum disappeared because men did not have to spend a longer time mating in order to protect their partner from being impregnated by others. (It should be noted that “prolonged intromission” is anything over three minutes.) “This may have been the final nail in the coffin for the already diminished baculum, which was then lost in ancestral humans,” Opie explained.

But remember: Despite the lack of bone, it’s still possible to fracture a penis, so, stay safe out there.

Here’s Why Humans Don’t Have a Penis Bone